AB1339 MUSCLE ULTRASOUND FOR THE DIAGNOSIS OF SARCOPENIA IN RHEUMATOID ARTHRITIS (RA).
Authors: L. Cano Garcia, J. Vacas, C. Dominguez, D. Ruiz, J. M. Martín Martín, F. G. Jiménez-Núñez
Journal: Annals of the Rheumatic Diseases (2022)

Background Sarcopenia is a muscular disease characterized by a loss of muscle mass and function. The condition is associated with chronic diseases and ageing and predicts disability, hospitalization and death (1). Due to chronicity and disability produced by RA, it is convenient to see the relationship with sarcopenia. Objectives To assess the diagnostic utility of ultrasound (US) for sarcopenia. Methods Cases: Outpatients, 65 years old or more, with RA (ACR/EULAR 2010 criteria) from the rheumatology clinics of 4 Spanish University Hospitals were randomly selected consecutively from rheumatology consultation since May 2021 to September 2021. Controls: Control subjects without rheumatoid disease were selected from family members or friends of the cases, paired by age, gender and social status from May to September 2021. Variable and measures: The main evaluated outcome was sarcopenia as defined in 2019 by the European Working Group on Sarcopenia in Older People (EWGSOP). Crossectional Ultrasounds (US) of the third proximal forearm were evaluated for the perpendicular distance (milimetres) between superficial surface of subcutaneous celular tissue and the deep surface close to the ulnae with two different measures (66% and 75%). Crossectional US images were also obtained of lower limbs, at an equidistant point between anterosuperior iliac spine and the upper border of the patella for measuring the distance between superficial surface of subcutaneous celular tissue and the deep interface of the femur with vastus medialis muscle with two different measures (50% and 75%). Handheld dynamometer was used to measure the strength in upper limbs. Body composition was evaluated using dual-energy X-ray densitometry. Statistics: A descriptive analysis, chi square y T-student tests were done to compare the main characteristics and results between patients and controls. Correlations between forearm US and strength and between thigh US and total DEXA were calculated by Pearson’s test. Results 76 patients and 76 controls were included in the study, 120 were women (78,9%), with media ± SD of age 74,7 ±6,98 of media and 32 (21,1%) were men, with age 70,1 ±3,78 of media. In comparation with controls, RA patients presented more frequency of sarcopenia (30 [19,53%] vs 6 [3,94%]; p=0,005) according to EWGSOP criteria. From the point of view of ultrasound, RA patients presented less muscle mass in cubital forearm and thigh. Control group presented larger size of muscle (Table 1). Table 1. Results measirements case-control in milimeters Control (m±ds ) RA (m±ds ) p-valor Right forearm 66% ulnar 42,92±8 38,72±9,33 0,003 Left forearm 66% ulnar 41,17±8,97 37,93±9,27 0,03 Left forearm 75% cubital 38,74±7,7 35,18±8,5 0,008 Right Thigh 50% FR+VI 30,9±7,46 28,09±6,31 0,011 Right Thigh 50%VI 14,5±4,26 13,08±4,27 0,042 Right Thigh 50% FR 15,26±3,6 13,5±3,28 0,002 Right Thigh 50% area FR 588±181,29 481,49±140,56 0,001 Lefth Thigh 50% FR+VI 27,67±8,9 22,37±8,26 &lt;0,001 Ultrasound measurements in forearm which showed a positive correlation with strength were: right forearm: 66% ulnar (r=0,364, p=0,001), 75% ulnar (r=0,365, p=0,001); left forearm: 66% ulnar (r=0,348, p=0,002), 75% ulnar (r=0,337, p=0,003). In the other hand, ultrasound measurements in thigh which showed a positive correlation with DXA were: right thigh 50% femoral rectus (FR)-vastus intermedius (VI) (r=0,255, p=0,003), 50% VI (r=0,256,p=0,003), 50% FR (r=0,265, p=0,002), 50% area FR (r=0,280, p=0,003), 75% FR-VI (r=0,357,p&lt;0,001), 75% VI (r=0,382,p&lt;0,001), 75% FR (r=0,240, R2=0,006), 75% area FR (r=0,218,p=0,023); Left thigh: 50% FR-VI (r=0,251, p=0,004), 50% VI (r=0,293,p=0,001), 50% FR (r=0,214, p=0,015), 75% FR-VI (r=0,347,p&lt;0,001), 75% VI (r=0,342, p&lt;0,001), 75% FR (r=0,295, p=0,001). Conclusion Muscle Ultrasound is a useful diagnostic tool to detect sarcopenia. It can be cost-efficient and faster when compared with DEXA and the results correlate consistently with the strength in forearm. Patients with rheumatoid arthritis are in high risk of suffering sarcopenia and US could be used to control the evolution of this condition. Disclosure of Interests None declared